Back when I was working for a company that did take home challenges, those who passed had their challenge as the topic of conversation for the final interview. For those who didn't, I gave written feedback, at least a page if not two.
My thinking was if someone took time to give me something, they deserved something in return, even if it wasn't a job.
If you have not been through the process you may not truly understand how nice (and rare) your thought process is.
Sadly I have chased up situations like that only to get told "you provided one of the strongest pieces of work, however, we decided not to proceed to interview" - or responding at all apparently.
The person already had gotten the job (they had not been informed yet), so it made no difference in the hiring decision.
They wanted to know which coding question they’d only gotten partial credit on during the screening phase, and why.
They had exceptional attention to detail after being hired too.